This International Standard specifies the requirements for a heavy-duty series of bolted bonnet steel gate valves for petroleum refinery and related applications where corrosion, erosion and other service conditions would indicate a need for full port openings, heavy wall sections and large stem diameters. This International Standard sets forth the requirements for the following gate valve features: — bolted bonnet; — outside screw and yoke; — rising stems; — non-rising handwheels; — single or double gate; — wedge or parallel seating; — metallic seating surfaces; — flanged or butt-welding ends. It covers valves of the nominal sizes DN: — 25; 32; 40; 50; 65; 80; 100; 150; 200; 250; 300; 350; 400; 450; 500; 600; corresponding to nominal pipe sizes NPS: — 1; 11/4; 11/2; 2; 21/2; 3; 4; 6; 8; 10; 12; 14; 16; 18; 20; 24; and applies for pressure Class designations: — 150; 300; 600; 900; 1500; 2500.